Invertable filter centrifuge

Abstract

An invertable filter centrifuge for separating liquid-solids mixtures comprises a rotatingly driven centrifugal drum, an invertable filter cloth arranged on the centrifugal drum, a filtrate housing for receiving and discharging the liquid filtrate separated from the liquid-solids mixture by means of centrifugation with a filter cloth turned inwards into the centrifugal drum, a solids housing for receiving and discharging the solids (filter cake) separated from the liquid-solids mixture during further rotation of the centrifugal drum with a filter cloth turned outwards and an annular gap surrounding the edge of the centrifugal drum in the region of the filtrate housing and the solids housing. Protection means are provided on the invertable filter centrifuge, with the aid of which a flow of a gaseous blocking medium can be generated in the annular gap surrounding the edge of the drum, this flow preventing any undesired transfer of gaseous, liquid and/or solid substances between filtrate housing and solids housing.

I claim: 
     
       1. An invertable filter centrifuge for separating liquid-solids mixtures comprising a rotatingly driven centrifugal drum, an invertable filter cloth arranged on the centrifugal drum, a filtrate housing for receiving and discharging the liquid filtrate separated from the liquid-solids mixture by means of centrifugation with a filter cloth turned inwards into the centrifugal drum, a solids housing for receiving and discharging the solids separated from the liquid-solids mixture during further rotation of the centrifugal drum with a filter cloth turned outwards and an annular gap surrounding the edge of the centrifugal drum in the area of the filtrate housing and the solids housing, wherein blocking gas generating means are provided on the invertable filter centrifuge, a flow of blocking gas effective in two opposing directions being generatable in the annular gap surrounding the edge of the drum with the aid of said blocking gas generating means, said flow effectively preventing any undesired transfer of gaseous, liquid and/or solid substances in the direction towards the filtrate housing and/or solids housing. 
     
     
       2. The invertable filter centrifuge of claim 1, wherein the blocking gas generating means comprise a pump. 
     
     
       3. The invertable filter centrifuge of claim 2, wherein the pump is connected to the filtrate and solids housings via pipe and control means and optionally generates overpressure in one of these housings so that the blocking gas flows through the annular gap into the respectively other housing. 
     
     
       4. The invertable filter centrifuge of claim 2, wherein the pump is connected to the annular gap surrounding the edge of the drum via pipe and control means and generates the flow of blocking gas directly in said gap. 
     
     
       5. The invertable filter centrifuge of claim 4, wherein the pump generates two flows of a blocking gas in the annular gap, one of said flows being directed into the filtrate housing and the other into the solids housing. 
     
     
       6. The invertable filter centrifuge of claim 1, wherein the blocking gas is air or an inert gas. 
     
     
       7. The invertable filter centrifuge of claim 1, wherein a seal is arranged in the annular gap between the edge of the rotating centrifugal drum and a stationary machine housing part. 
     
     
       8. The invertable filter centrifuge of claim 1, wherein an exhaust gas pipe is provided, the blocking gas flowing out of the filtrate housing or solids housing being introduceable into said pipe. 
     
     
       9. The invertable filter centrifuge of claim 8, wherein the exhaust gas pipe contains a pressure-maintaining valve. 
     
     
       10. The invertable filter centrifuge of claim 1, wherein a gas-shuttle pipe with a check valve is provided between filtrate housing and solids housing. 
     
     
       11. The invertable filter centrifuge of claim 10, wherein the pump is arranged in the gas-shuttle pipe. 
     
     
       12. The invertable filter centrifuge of claim 2, wherein the pump is arranged in the gas-shuttle pipe. 
     
     
       13. The invertable filter centrifuge of claim 1, further comprising a solids filter for the flow of blocking gas exiting from the solids housing. 
     
     
       14. The invertable filter centrifuge of claim 1, further comprising a liquid separator for the flow of blocking gas exiting from the filtrate housing.